By following what has been done in [1]}, let us localize eq:mMomEq at a generic \(\Omega _i\)  cell center, we get:
\(\tilde{\mathbf {u}}_i = \frac{\mathbf {H}(\tilde{\mathbf {u}})}{a_i} - \frac{\nabla \overline{p}_i}{a_i}.\) 
